In episode 30, I talk about the use of zinc lozenges to fight colds. While nutritional zinc does support the immune system and your immunity may benefit from zinc supplements or zinc-rich foods, this has nothing to do with the use of zinc lozenges to kill colds. The science behind their use is strong, but it also suggests that most of the dozens of zinc lozenges on the market are absolutely useless. The only ones I currently use and recommend are Life Extension Enhanced Zinc Lozenges. Listen in to find out why!

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This episode is brought to you by Kettle and Fire bone broth. I use their 24-hour simmered bone broth as a source of glycine-rich collagen and other nutrients that slowly release from the bones and the marrow inside them. A team of chefs designed the recipe, so it’s delicious to the max.  And the state-of-the-art packaging makes it the only bone broth on the market that is cooked in the traditional way and has no additives or preservatives, yet stays shelf-stable for up to two years, making it easily available at a moment’s notice. Head to kettleandfire.com/chris to get $10 off your first order.

This episode is also brought to you by US Wellness Meats. I use their liverwurst as a convenient way to make a sustainable habit of eating a diversity of organ meats. They also have a milder braunschweiger and an even milder head cheese that gives you similar benefits, as well as a wide array of other meat products, all from animals raised on pasture. Head to grasslandbeef.com and enter promo code “Chris” at checkout to get a 15% discount on any order that is at least 7 pounds and is at least $75 after applying the discount but under 40 pounds (it can be 39.99 lbs, but not 40). You can use this discount code not once, but twice!

Show Notes for Episode 30

In this episode, you can find all of the following and more:

00:37     Cliff Notes
12:55     Zinc status is important to immune function, but that’s not what this podcast is about. Nevertheless, I go through basic tips of getting good zinc nutrition.
16:48     My typical use of zinc for colds has missed the point.
18:08     Zinc has to be a lozenge to kill the common cold. In fact, the original discovery of its role in killing the cold was born from a child refusing to swallow a tablet and letting it dissolve in her mouth.
20:15       The main mechanisms by which zinc kills colds.
21:10       Importance of zinc ionization in nasal and adenoid tissue.
23:26      Importance of taking it at the right time (first couple of days of a cold).
27:10       pH of nose and throat tissue, not saliva, is important.
27:55       Gluconate and acetate are effective, but acetate is twice as effective as gluconate.
29:08     Astringency and metallic taste must be present, but are not sufficient.
31:35      Food acids used to cover taste such as citrate or tartrate cannot be present.
34:30     Magnesium cannot be present in a form that ionizes in the nose and throat.
36:30     Time of contact with membranes makes concentration, time to dissolve, and frequency of use important.
39:50     Meta-analysis of randomized controlled trials
42:20     Meta-analysis of individual patient data and lack of effect of age, sex, baseline cold severity, allergy status, race, and ethnicity
44:00      George Eby’s model showing a strong correlation between predicted ionic zinc yield and efficacy in RCTs suggests that the right dose of the right formulation taken at the right time in the right way could constitute a true cure of the common cold.
45:45     Only Life Extension Enhanced Zinc Lozenges fit the criteria.
54:13      My story with Life Extension zinc acetate lozenges.

How to Get the Right Zinc Lozenges at the Best Price

By far and away, the most cost-effective way to get the Life Extension Enhanced Zinc Lozenges right now is to order four from the Life Extension web site. To do so, click on “Select Multi-Unit Discount” and change it to “4 Units.” Until January 31, Life Extension’s “Super Sale” has them 32% off when sold singularly and 55% off when sold in a pack of four. Shipping costs $5.50, but spread across four bottles it’s only $1.37 per bottle. Compared to the Amazon Prime option (which, in any case, is out of stock until December 30), despite its free shipping, buying a four-pack from Life Extension saves 39%. Compared to the least expensive non-Prime options on Amazon, it saves 28%.

Personally, I had the misfortune of accidentally buying from one of the non-Prime sellers on Amazon, and in the process accidentally paid for shipping when I thought I was getting it free, and on December 26 its current status is “Expected December 16, 2016: On the Way.”

One bottle contains 30 lozenges, which, taken correctly, is sufficient to knock out a cold in a single person. The cost of one bottle, with shipping, when ordering four from Life Extension is $6.77.

Having more than one bottle is great for frequent cold sufferers, households where more than one person may get sick, or someone who wants to be prepared for next time. To use this properly, you need to have it on hand before you get sick. Therefore, at least through January 31, 2017, I think the best way to get this is to order four from Life Extension and the second best is to order fewer than four from them.

Should You Take Copper While Taking Zinc Lozenges?

While it might not be necessary, I think it’s a good idea to take 2-3 mg of copper with each meal while taking the zinc lozenges, and to stop both as soon as the cold is gone. This is because the portion of zinc that reaches the intestines can trap copper in intestinal cells and cause it to soon after be lost in the feces.

I don’t have strong opinions about which copper supplement is best, but here are the options that seem most cost-effective:

• Source Naturals at Iherb is $5.67 for 120 3-mg tablets.
• Solgar at Amazon is $8.05 for 100 2.5-mg tablets and is eligible for Prime and fulfilled by Amazon.

My Cold Season War Chest of High-Impact Supplements

This podcast was a result of research I did for My Cold Season War Chest of High-Impact Supplements, which was a gift to my email list. This guide provides a broader context of supplements I find useful during cold season. If you subscribe to my email list using this link, you will immediately get the opportunity to download the War Chest email as a pdf.

Research Related to Episode 30

George Eby, Zinc lozenges as cure for the common cold — a review and hypothesis.

Harri Hemilä, Zinc lozenges may shorten the duration of colds: a systematic review.

Hemilä, Petrus, Fitzgerald, and Prasad, Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis.

Transcript of Episode 30

This is Chris Masterjohn, and you’re listening to Episode 30 of Mastering Nutrition where we talk about how zinc definitely fights the cold, but you’re probably using the wrong kind.

This is Mastering Nutrition Podcast with Chris Masterjohn. Health and nutrition news you can use on the daily. Are you ready?

00:37   Cliff Notes

All right, for those of you who want the cliff notes, this is about the importance of zinc as a lozenge, as zinc acetate, and as free of the wrong ingredients for use in the common cold. The right use of a zinc lozenge is probably almost essentially a cure for the common cold, and to use it correctly, it has to be used immediately. As soon as you realize that you have cold symptoms, it has to be a lozenge. It has to be zinc acetate. It has to have about 18 milligrams of zinc per lozenge. It has to take about 20 to 30 minutes to dissolve in your mouth and it has to be taken about every two hours while you’re treating the cold symptoms. It has to have a metallic taste. It has to be astringent. It has to be free of anything that ends in “ate” or “ic acid” in the ingredients. It has to be free of magnesium. Magnesium stearate would be an exception to both of those rules because it’s insoluble and other stearates are fine even though they end in “ate”. And if those things are satisfied, it should be highly effective. The only one that I recommend is Life Extension zinc acetate, enhanced zinc acetate lozenges. You can find buying recommendations at chrismasterjohnphd.com/zinc. You can find the show notes for this at chrismasterjohnphd.com/30. And you can get the related email from which this all came about as a research initiative on my part by going to chrismasterjohnphd.com/colds. If you want the nuance and sophistication and explanation, listen on right after this word from my sponsors.

This episode is brought to you by Kettle and Fire bone broth.

If you’ve been following my work for a while now you know that I’m a huge advocate of bone broth. It’s rich in collagen, and collagen is the best dietary source of the amino acid glycine. It’s great for your skin, hair, nails, your bones and tendons, and all of your connective tissues. It supports detoxification and helps regulate inflammation. Plus, in our society we tend to eat a lot of muscle protein from meat products, and similar proteins from eggs and dairy products. These proteins are rich in the amino acid methionine, which actually raises our need for glycine. So it’s even more important for us to balance these proteins with collagen-rich foods, and regularly consuming bone broth is a great way to do that.

Now, I think it’s great to make your own bone broth. And in fact, I try to do that myself. But it definitely isn’t easy, especially for someone who works a busy job and doesn’t have a lot of time to cook. When I am able to make my own, I make it as simple as possible because I’m struggling just to find the time to make it and I don’t have the time focus on the art needed to make it flavorful.

That’s where Kettle and Fire comes in. Kettle and Fire bone broth is made from all organic ingredients, and the bones are taken from certified 100% grass-fed and grass-finished cattle. It’s simmered over low heat for 24 hours, so it gels just like the best of homemade broth and it’s rich in the nutrients that slowly release from the bones and from the marrow inside them. To top it all off, a team of chefs designed the recipe, so it tastes far more delicious than anything I could make myself and, let’s face it, probably anything you could make yourself too.

Now I’m sure all of that sounds fantastic. It certainly does to me. But it really wouldn’t mean much of anything if it couldn’t get delivered fresh to your home and stay fresh right through the moment you need it. And that is where Kettle and Fire really hits a homerun. These guys invested $6 million in state-of-the-art packaging technology that allows them to deliver a fresh, never-frozen product with zero additives and zero preservatives that’s so shelf-stable that, as long as you keep it sealed, it stays fresh at room temperature for up to two years.

So it tastes like you’ve had a chef slaving over your stove in the hours leading up to your meal, but it’s as if that chef will work for you at a moment’s notice, as if that chef lives in your pocket. Because it only takes seconds to reach for some Kettle and Fire broth, take it off the shelf, open it up, and begin pouring.

In addition to saving you some time in the kitchen and making your meals more nutritious and more delicious, Kettle and Fire can also save you some money. By using the special link kettleandfire.com/chris, you can get $10 off your first order. The most cost-effective way to get Kettle and Fire bone broth is to subscribe to six packages per month. Even a one-time order of six packages though will get you free shipping. However you want to do it, just be sure to use the special link kettleandfire.com/chris to get your discount.

This episode is brought to you by US Wellness Meats.

I discovered this company at Paleofx this spring and I fell in love with them as soon as I tried their liverwurst.

For years, I’ve known that I feel best when I eat a diversity of organ meats like liver and heart. I have a clearer mind, feel more energetic, and my energy is much more stable between meals, but it’s so hard and so time consuming to make a sustainable habit out of preparing and cooking organ meats.

US Wellness liverwurst is 15% heart, 15% kidney, and 20% liver, with the remainder grass-fed beef. That’s a whopping half organ meat. It takes zero time to prepare, tastes great, and finally makes consuming a diversity of organ meats a habit that I can easily sustain.

But just because I’m obsessed with their liverwurst doesn’t mean it’ll turn out to be your favorite. US Wellness makes an even milder braunschweiger that’s 35% liver and 65% beef. And if you have a really sensitive palate and just want to get your feet wet with organ meats, their head cheese delivers the mildest taste with 15% heart, 15% tongue, and the remainder beef.

They also sell an incredible array of other meat products in practically any cut you could want, all from animals raised on pasture.

Now, this isn’t just about high-quality, grass-fed meat products that can up your nutritional game, and save you time in the morning. It’s also about saving money. And that’s because I worked out a special deal for you. As a member of my audience you can go to grasslandbeef.com, order whatever you want as long as your total order is at least seven pounds and at least $75 after applying the discount, and as long as it’s under 40 pounds, you can enter the promo code “Chris” at checkout. Putting my name in the box earns you 15% off your order, and since you can order up to 39.9999 pounds of meat at that discount, you can potentially save a lot of money. If you’re on the fence or not ready for a big order, don’t worry. You can use the promo code “Chris” not once but twice. So order the minimum your first time and if you love this stuff as much as I do, you can order the max the second time around and get the same level of discount. Or, just max out your order both times and get just shy of 80 pounds of meat at the discounted price. Either way, head over to grasslandbeef.com and make sure you enter “Chris” at checkout to get the discount.

So first of all, if you celebrated Christmas yesterday or you started celebrating Christmas and are still, Merry Christmas. If you are celebrating any other holiday, happy holidays to you. Whether you’re celebrating holidays or not, it is not only the holiday season, it’s also cold season. So I want to put out this podcast because — so the origin of this podcast came out when I was putting together an email for my email list about the supplements that I usually use in cold season, and I was driven to do some research because as I was putting it together, for some things I was pretty familiar with the evidence, and for others I thought, you know what, let me let me see how well I can back up the things that I’m doing myself. And I came to realize that there is a ton of very clear research out there about what you should be using for zinc, and chances are like me, if you’re doing anything with zinc, you’re doing it totally wrong. And if you’re not doing anything with zinc and you are not one of the quarter or so of the population that almost never gets colds or whatever that percentage may be, then you are missing out on a huge opportunity. So if you are on my email newsletter and you didn’t to get this email, it was called My Cold Season War Chest of High-Impact Supplements. I imagine if you keyword search your email for war chest, you should find it pretty easily. If you’re not on my email list and you want that email, then you can go to chrismasterjohnphd.com/colds and you can sign up for my newsletter using that specific form. You’ll immediately get that particular email. And then that goes over in general the things that I think are really helpful from a prevention standpoint but more so from an immune system first aid kit perspective, like what should you have in your house in order to make sure that if something happens and you get sick you have those things available. So check that out if you want.

What I want to do now is take this one particular concept of zinc lozenges that came out of my research for that email and expand on it because this is so misunderstood and misused that it really deserves its own podcast episode.

12:55   Zinc status is important to immune function, but that’s not what this podcast is about. Nevertheless, I go through basic tips of getting good zinc nutrition.

So first of all, zinc is important to the immune system and that has nothing to do with what I’m talking about today. Now, if you aren’t getting enough zinc, you will probably benefit from increasing zinc-rich foods and you’ll probably benefit from taking zinc tablets or zinc capsules as prevention and if you get sick with a cold or really with any other kind of illness. And if you look at zinc in foods, we can say a few things. First of all, the foods that overwhelmingly stand out as good sources of zinc are oysters, beef and cheese. I say beef, red meat more generally, so oysters, red meat and cheese. The reason I single out cheese is that liquid milk is not all that rich in zinc and the cheese concentrates it. And I should also say that within those foods, oysters are by far and away the richest in zinc. If you compare beef and oysters, they’re really in two different categories. If we use the RDA for zinc as a metric, you would have to eat oysters maybe once a week to get your zinc requirement, you would have to eat beef every day. We can also say that animal foods are much richer than plant foods generally. And then the last thing we could say is that zinc is much more bioavailable from animal foods than from plant foods.

So if you are eating a largely plant-based diet, then you may well benefit from more zinc-rich foods or from zinc supplements for your immune system. And also, the overwhelming determinant of zinc absorption is the phytate content of a meal. So if you are eating a lot of grains, nuts and seeds, basically anything that’s taxonomically a seed that can be planted in the ground to sprout at a certain time and grow a plant, that probably has a considerable amount of phytate in it. Phytate is kind of a storage house for minerals. So if there were no phytate in the world, then a seed would not have any control over when it germinates and seeds would largely be wasted because they would germinate at times that are not well-conditioned for plant growth. Because of phytate, the conditions that allow germination and allow a successful growth of a plant are the same conditions that will neutralize the phytate and release the minerals so they can become available for germination and plant growth. So if you do eat a lot of nuts and seeds and grains, then sprouting them or soaking them or fermenting them can help reduce the phytate concentration. If you do eat phytate-rich meals, the zinc in the meal is going to be less bioavailable, but also any zinc supplements you add to the meal will be less bioavailable. And so if you take zinc supplements, then it can be helpful to take them an hour before a meal, especially if those meals are rich in phytate. So if any of those things apply to you, then certainly looking at your zinc nutrition can benefit your immune system. But that is not the focus of this podcast. That is not what this is about.

16:48   My typical use of zinc for colds has missed the point.

So for me I will say that I had to read about zinc and the colds largely in tertiary sources, for example, in books about nutrition that you can use for healing, and I had not really delved into the primary and secondary literature, meaning the actual studies, the reviews of those studies and so on that are in the peer-reviewed literature. So I had never really understood the nuances and sophistication involved, and it had been my typical practice to use 100 or 200 milligrams of zinc as tablets when I would have a cold. And yes, that may help if, like I said, before your zinc nutrition is not that great, but that really has nothing to do with the very robust literature around zinc lozenges and the common cold.

18:08   Zinc has to be a lozenge to kill the common cold. In fact, the original discovery of its role in killing the cold was born from a child refusing to swallow a tablet and letting it dissolve in her mouth.

So let’s wind back the clock to how this literature first got going. The initial story that led to this research contains in itself the key to understanding why the zinc should be in a lozenge, and this story began with George Eby’s three-year-old daughter who had leukemia and who was suffering from very frequent colds around the time that she first developed the leukemia, and she was being treated with 50 milligrams of zinc gluconate to try to improve her zinc status and improve her T cell responsiveness which is an indicator of her immune strength. But she refused to swallow one of the tablets and let it slowly dissolve in her mouth, and that night she was suffering from a bad cold and it disappeared within a few hours. So Eby saw this and took note of it, and then tested whether the zinc tablet, when dissolved in her mouth, could make future colds go away, and it seemed to be replicable. And then he stimulated interest in testing this and other people, and it seemed to be replicable. So George Eby and his colleagues produced the first randomized controlled trial in 1984 showing that zinc lozenges could decrease the median duration of a cold by just under five days and the mean duration of a cold by seven days. Now if you think about how long a cold usually lasts, that’s almost getting rid of the cold.

20:15   The main mechanisms by which zinc kills colds.

So there are a number of things that we can say, however, about what makes a zinc lozenge effective, and this means that almost every zinc lozenge on the market, and there are at least about 40 of them, is useless. So if you’ve been taking zinc tablets or capsules for the common cold like I have, then you are not and have not been taking advantage of the science around zinc lozenges. At best, you’ve been improving your zinc status and having a general effect on your immune system, but you have not been taking advantage of what was happening in that three-year-old girl with leukemia and killing the cold virus with the zinc lozenge.

21:10   Importance of zinc ionization in nasal and adenoid tissue.

So let’s take a little bit of a look at how this works and what we should expect to be the characteristics of an effective zinc lozenge. So ionic zinc, which means positively charged zinc that is free and not bound to anything else, has effects on nasal tissue and adenoid tissue which is the lymph tissue in the throat — these are the two major sites of infection during a cold — that inhibit the activation of viral polypeptides that are used in the replication of that cold virus and inhibit the production in our cells of a molecule called ICAM-1 which stands for Intercellular Adhesion Molecule 1 and is essentially the dock that allows the virus to grab hold of the cell and enter it.

Now, right away we can say two things from this. First of all, this is ionic zinc and not zinc salts. So if you look at any zinc product on the market, you’ll see that it’s some salt of zinc. For example, zinc gluconate, zinc acetate, zinc glycinate, zinc picolinate, zinc on and on, orotate and so on and so forth. What this means is that the positively charged zinc ion has been bound to something that’s negatively charged like glycinate or gluconate or acetate or orotate or picolinate. And when the positive and negative charges are conjoined, what you have is a salt that doesn’t have any charge. Those charges have been neutralized by those two things binding together. So the only ones that will be effective are the ones that will release zinc in the free ionic form in the relevant tissues at the right time.

23:26   Importance of taking it at the right time (first couple of days of a cold).

The second thing is that you need to start taking the zinc almost immediately after being infected or at the very first sign of symptoms because what zinc is doing is interfering with the replication of the virus and its initial ability to infect you. And if you look at the typical sequence of events when you get a cold, it basically happens like this. You have an incubation period of about a day, might be a little bit shorter, might be a little bit longer, but you’re not experiencing any symptoms yet, and you are being infected and you are already contagious. Then you have two or three days where viral replication and symptoms are both increasing. And then at the two- to three-day mark the viral replication is peaked, and already, if you do nothing for your cold, the virus is actually declining thereafter, and at five days the virus is basically undetectable, whereas your symptoms may be running up through a whole week or maybe even a little bit longer in some people.

So basically, if you start using zinc lozenges two to three days into your cold, it’s probably not going to do anything because you’re using a product that’s meant to interfere with the replication of the virus, and the virus is already declining in numbers. You may feel sicker and sicker and sicker three days into your cold. That’s because of your immune system and the virus has like done its job, washed its hands of you and is leaving now while you just keep getting sick in terms of your perception of the symptoms. So you really only have two to three days to do anything at all, and if you want the maximum effect, you want to hit the virus at the stage. As soon as you know that it’s in there, you want to smack it with something that’s going to stop replication in its tracks. So those two things that are super important are, number one, it has to release ionic zinc into the relevant issues, and number two, it’s got to be early enough to stop the replication in its tracks.

Now, what’s going to release zinc into the relevant issues? Well, first of all, the delivery method matters. It has to be a lozenge, because if it’s a tablet or a capsule, it’s releasing ionic zinc into your stomach and it’s already too late. Now, there have been nasal sprays that have been advocated, but actually, I don’t even think it’s allowed anymore because the nasal spray can actually kill your sense of smell and damage the lining of your nose and what you want is a lozenge where it’s going to release in your mouth. And it’s been demonstrated that the zinc that’s released in the lozenge will actually travel into your nasal tissues, and of course it’s more obvious that it can also reach your throat tissues, and your nose and your throat are the two most relevant issues.

27:10   pH of nose and throat tissue, not saliva, is important.

An additional thing that’s important is the type of zinc, meaning what zinc salt is being used, and there has been some controversy over this in the literature because some people have advocated the idea that a salt that releases ionic zinc at the pH of the saliva is what’s relevant, but it’s not. Salivary pH is five which is over a hundred times more acidic than the pH of our cellular environment, which is around 7.4. There are a lot of zinc salts that will release ionic zinc at the pH of the saliva. There are only a handful that will release it at physiologic pH of 7.4.

27:55   Gluconate and acetate are effective, but acetate is twice as effective as gluconate.

Out of the salts that are available in lozenges, only zinc gluconate and only zinc acetate will release any meaningful amount of ionic zinc at that pH. Now, if you look at gluconate and acetate, at pH 7.4 zinc gluconate is 50% ionic and zinc acetate is 100% ionic. So what we should predict from this is that only zinc gluconate has any usefulness at all, but it zinc acetate should be twice as effective. If you look at the dozens of zinc lozenges on the market, you will find that most of them are not gluconate or acetate and at best, except for the only one that I recommend here which is Life Extension enhanced zinc acetate lozenges, almost all of the ones that are gluconate or acetate are gluconate which is the one that’s half as effective.

29:08   Astringency and metallic taste must be present, but are not sufficient.

Now, part of the reason there’s been a proliferation of non-effective forms is that zinc, when it is in your mouth, has a metallic taste, and it’s astringent, which means that it dries out your mouth tissues and those are not pleasant. So there’s been a huge effort to make zinc lozenges more palatable and to taste pleasurable. Well, here’s the problem. What makes the metallic taste and the astringency, it’s the presence of ionic zinc in your mouth. So if you have a zinc lozenge that doesn’t have a metallic taste and isn’t astringent, you can be certain that it’s not doing anything at all to help your cold. In fact, as we’ll talk about in a few moments, it may actually make your cold worse.

Now, conversely, it is not necessarily the case that something that tastes metallic and is astringent is a guarantee of its efficacy, and that’s because what determines the mouthfeel and the taste is whether the ionic zinc is present in your saliva. And like I said before, salivary pH is over a hundred times more acidic than the pH of your nose and throat tissues, and that means that the subset of zinc lozenges that produce a metallic taste and astringency is much larger than the ones that would be effective at killing the common cold. So we can develop a simple rule from that which is that the absence of metallic taste and astringency ensures that the lozenge is useless, but the presence of metallic taste and astringency does not ensure that the lozenge is useful. To put it in other words, astringency and metallic taste are necessary but not sufficient for effectiveness against the cold.

31:35   Food acids used to cover taste such as citrate or tartrate cannot be present.

Now, there’s another problem that goes beyond of the type of zinc and that’s what else is in the lozenge? This also has been a huge problem created by the need for something tasty. That is that food acids such as citrate or tartrate will very tightly bind zinc. So let’s say you have a zinc gluconate citrate. The zinc gluconate will release 50% zinc in the relevant tissues, but then the citrate that’s in that lozenge will quickly bind up the zinc and form an insoluble salt. One of the zinc products that was shown to be useless was one that used bicarbonate and tartrate to make it effervescent, and so they tried to go even beyond just not having metallic taste and produce something interesting going on in the mouth, and the result was a totally useless product. In fact, if you look at the studies where there’s citrate or there’s tartrate in the zinc product, they seem to suggest that it worsens the cold and makes it last longer. So I mean the end result is — I mean just think about this. Like if the product is effective — if all the products are useless, then what you want is something that tastes good because you want your lozenge to make your throat feel a little bit better, you want the person to psychologically feel like they’re doing something, and you want to make it sound science-y and say this has zinc gluconate in it or whatever. It’s like the determinant of whether the people like it has nothing to do with its effect on the cold because it doesn’t actually do anything at all for the cold, and so it’s really important that it doesn’t taste bad.

But if we bring a little bit of science and a reality to this, what would you rather have? Something that was not very pleasant in your mouth that you suck on for a couple days or if you don’t have cold symptoms or you actually escape the cold or would you rather have the lozenges taste better and get sick for a week? I mean come on, like it’s a no-brainer here. But it getting a no-brainer all depends on it actually working, and I hope by the end of your podcast you’re convinced that this stuff actually does work.

34:30   Magnesium cannot be present in a form that ionizes in the nose and throat.

Now, there’s another thing that shouldn’t be in the lozenge and that’s magnesium. Magnesium itself if you eat it is good for your immune system, but ionic magnesium at high concentrations when delivered to nasal and throat tissues will not only nullify the zinc but will increase the replication of the cold virus and make you get sick for longer.

So to sum up the properties here, it has to be a lozenge, it has to be either zinc gluconate or acetate but it should be acetate. Why would you use gluconate when it’s half as effective? It can’t have any food acids or other acids added for flavor such as citric acid or any other acids in the ingredients and it cannot have magnesium in it. Furthermore, there’s been one product tested and found to be useless or harmful and it was produced with very high heat in the presence of fats and like there was palm oil in it, I believe, and the high heat basically produced insoluble zinc waxes with the fatty acids. On that very note, it’s important to point out that the lubricants that are sometimes used in supplements such as magnesium stearate or other stearate, for example, are insoluble, and that’s the reason that they’re useful in the supplement. But it also means that they don’t yield an acid that could bind to the zinc and they don’t yield high concentrations of ionic magnesium, so magnesium stearate or vegetable stearate or something like that actually wouldn’t be a problem here.

36:30   Time of contact with membranes makes concentration, time to dissolve, and frequency of use important.

Now, another key principle that we would predict to be important is the time of contact with the cells. Mechanistically, what’s important is that ionic zinc is diffusing across the membranes of the nasal cells and the adenoids cells in the lymph tissue of the throat and is actually present there long enough to favor accumulation of free zinc inside the cell. Mechanistically, time of contact is a major important factor there. Clinically, the use of the zinc supplement in terms of how concentrated is the dose and how long does it take to dissolve in the mouth and how often is it taken seems to back up this concern. So, on a practical level, you want the lozenge to take at least 20 to 30 minutes to dissolve in the mouth. If it dissolves a lot quicker than that, it’s not going to have adequate time to diffuse across the membranes. Second of all, you want it to be high enough in concentration. So zinc lozenges that have at least 12 milligrams or 18 milligrams would be even more effective are going to provide more zinc for a longer time there. And then finally, it has to be taken every two hours. Every three to four hours seems to be insufficient. Every two hours, what you’re basically doing is you’re continually replenishing the free zinc frequently enough that the cellular zinc doesn’t get depleted to allow the cold virus to start replicating again.

So what then is the evidence here? Well, like I said before, the first randomized controlled trial was in 1984 and was put out by George Eby who was the person who made the initial observation about his three-year-old daughter with leukemia recovering from colds with the accidental zinc lozenge. Now, since that time, I should say that a lot of what I’m putting out here is resulting from George Eby’s analysis, and he does have financial interest in this. He at one time headed a patent for his zinc lozenges. It’s now expired and he has profited from the patent royalties as well as sales of products from his website, coldcure.com. But my perspective here is good for him because he was a pioneer in this. In any case, what he has advocated here has been borne out by independent research from other people who don’t have that financial interest in it.

39:50   Meta-analysis of randomized controlled trials

In the show notes for this episode, which can be found at chrismasterjohn.com/30, there was a meta-analysis produced by — I don’t know if I’m getting the pronunciation of his name right — Harri Hemilä. He looked at the effect of dose and formulation in randomized controlled trials. When they divided up the trials into those that gave less than 75 milligrams per day of zinc during the cold and those that gave more, zero trials that gave less than 75 milligrams per day of zinc were effective and seven out of eight of the trials that gave more than 75 milligrams per day were effective. When they divided the trials between those that used zinc acetate and those that used the non-acetate form, zinc acetate was associated with a 42% reduction in the duration of colds, and that was consistent across the trials, and non-acetate formulations were associated with a 20% decrease in the duration of the cold, and those effects were inconsistent across trials. So both of those things from the clinical evidence from randomized controlled trials back up what we would say mechanistically, which is you have to provide enough zinc often enough; thus, high dose works, low dose doesn’t; and you have to provide ionic zinc in the formulation of zinc that produces the most ionic zinc, and that’s mainly acetate and gluconate. And then mechanistic evidence indicates that at the pH of the nasal tissue and the throat tissue that’s relevant, acetate releases twice as much ionic zinc as gluconate. These randomized controlled trials show that acetate is twice as effective as gluconate.

So all of this converges the clinical evidence, the mechanistic evidence, the anecdotal evidence, all of it converges towards the efficacy of zinc acetate lozenges that are provided frequently at high doses.

42:20   Meta-analysis of individual patient data and lack of effect of age, sex, baseline cold severity, allergy status, race, and ethnicity

Hemilä and several other researchers, not including George Eby but including several other researchers who had done important work in these randomized controlled trials, produced a meta-analysis of the individual patient data from the highly effective zinc acetate trials. So what they did is they took three trials where high dose zinc acetate was used. They extracted all of the individual patient data, so that amounted to almost 200 patients, and then they looked at okay, if we break down the individual effects of these patients, does it matter whether they are smokers, does it matter whether they have allergies, does it matter whether their baseline cold severity was higher or lower, does it matter how old they were, does it matter whether they were male or female, does their race or ethnicity matter, and across all of those variables, the effective high dose zinc acetate was consistent, suggesting that its mechanism of action and its efficacy is not affected by allergy status, smoker status, baseline cold severity, age, sex, race or ethnicity.

44:00   George Eby’s model showing a strong correlation between predicted ionic zinc yield and efficacy in RCTs suggests that the right dose of the right formulation taken at the right time in the right way could constitute a true cure of the common cold.

Now, finally, the variation in the dose of zinc is sevenfold across the trials, and to say lower than or more than 75 milligrams a day is a very crude metric of determining the efficacy. So one analysis that George Eby did was he looked at the actual chemical properties of the lozenges and the dose of the lozenge and the other ingredients in the lozenge to come up with an index of how much ionic zinc should have been released into the nose and throat of the people in those trials, and then analyzed the efficacy of the lozenges based on that measure as a continuous variable. And what he found was that there was a very strong correlation between the amount of ionic zinc that you would predict would be released and the efficacy of the lozenge to the extent that the release of ionic zinc could explain 70% of the effect of the variation and the effect on the duration of the cold across those trials. And predicting from his model, a zinc lozenge that contains 18 milligrams of zinc that takes 20 to 30 minutes to dissolve in the mouth that is taken every two to three hours should be associated with a reduction in cold duration by about seven days, which is effectively more or less a cure for the common cold. This is remarkable because, as you know, everyone says that there is no cure for the common cold, and I think that he makes a very strong, very scientific, very rigorous case that the right zinc acetate lozenge used the right way may effectively be a cure for the common cold.

45:45   Only Life Extension Enhanced Zinc Lozenges fit the criteria.

Now, I searched for any lozenges that fit the criteria of the research that I was looking at, and what I found was the only one that I could find was Only Life Extension Enhanced Zinc Acetate Lozenges, and the enhanced is super important because Life Extension makes other zinc lozenges that do not fit this criteria. Remarkably, I searched iherb.com for zinc acetate and what I got was tons of zinc lozenges that don’t have any zinc acetate in them, and I don’t know why they were turning up, but I think it’s because the people marketing these lozenges know that people who know what they’re talking about are going to be searching for products with zinc acetate in them so they probably put that in the keyword searches. But I know at least in one case, it’s because there were people leaving comments saying this is a fantastic product because it has zinc gluconate which is the second most effective type of zinc to be in a lozenge, and in parenthesis, zinc acetate is the most effective. But why is that an awesome product if it’s the second best? And it’s not the second best like it’s 98% as effective as acetate. It’s 50% as effective as zinc acetate. So if something is twice as effective, why on earth would you make or take the thing that’s half as effective? It makes no sense.

Now, I have no brand loyalty to Life Extension. You’ll see that if you looked at my supplement review in The Ultimate Vitamin K2 Resource at chrismasterjohnphd.com/k2, you’ll see that I’m not a big fan of Life Extension’s vitamin K2 supplements. So I have no loyalty to them here. But I absolutely believe that Life Extension Enhanced Zinc Acetate Lozenge is the only zinc lozenge on the market that I will take at least from what’s available right now. And until that changes it’s the only one I’ll ever take now that I’ve looked at this research, and it is the only one that I will recommend now and will remain the only one I recommend unless someone points me to another product that meets these criteria that I overlooked or someone gets off their butt and actually starts making zinc lozenges that fit the scientific criteria, unlike almost every zinc lozenge on the market.

So if you go to chrismasterjohnphd.com/zinc, that will lead you to my analysis of where you can buy that product and which is the best way to buy it. Basically that comes down to Amazon or Life Extension’s own website, and there are some pros and cons to each of those that mainly revolve around the shipping fees and ease of online ordering and so on. So if you want that analysis, go to chrismasterjohnphd.com/zinc. And if you want at no extra cost to you to support the website financially, using my links in that section will offer a small revenue toward me through the affiliate links.

Now, if you don’t have access to the Life Extension products because of where you are in terms of maybe they don’t ship to your area, then basically what you want to do is you want to look for a product that, number one, has a high dose. It should have at least 10 to 20 milligrams or somewhere between 10 and 20 milligrams of zinc per lozenge. It should be zinc acetate if you can find it, and if you can’t find it use zinc gluconate. It should not have anything that ends in “ate” or anything that ends in “ic acid” in the ingredients. No citrate, no citric acid, no tartrate, no tartric acid, for example, bitartrate, whatever. Nothing that ends in “ic acid” or “ate” should be in the ingredients. The only exception to “ate” would be anything used as a lubricant such as magnesium stearate. And the ingredients should be relatively simple. It’s okay provided that it’s not in a candy form. So if it’s like glossy and feels and looks and tastes like a candy, it’s probably been treated in ways like with high heat and other things that could decrease the efficacy of the zinc. There shouldn’t be any magnesium in it. And when you taste it, it should taste a little bit metallic. It should feel a little bit astringent, and it should take 20 to 30 minutes to dissolve in your mouth.

In any case, I recommend Life Extension’s product, Enhanced Zinc Acetate. I would just use it as on the label. So first of all, I would start taking this at the first symptom that you think has even 5% probability of being a cold symptom, like you sneezed a couple of times because of the season and what you were doing. It seems plausible that that might have been the first sneeze of your cold. There’s no harm in taking one of these lozenges. And then reevaluate. If it happens again and the overall pattern seems like you might be getting sick, continue to take the zinc acetate. If everything goes away and you think it was a fluke and you don’t want to waste your money, stop taking the zinc acetate, but you want to be as proactive as you can here. And once you’re on a roll and you have good cause to believe that you’re treating yourself for the cold, you want to take it every two hours. Let’s say you are awake for 16 hours. That gives you eight or nine opportunities to take this. Let’s say you take eight a day, you are hitting about 140-150 milligrams of zinc.

In my opinion, if you do that for more than a day or two, you should supplement with a little bit of copper. Once you get over 40 to 50 milligrams of zinc supplementally, you want to make sure that your zinc to copper ratio is somewhere between two to one and fifteen to one in favor of zinc. I think the simplest way to do that is just to take two or three capsules. Probably if you look at copper supplements, you can find 2 milligram supplements. I would take two or three of those while you’re taking the high dose zinc lozenges. Now, it may be the case that you don’t need to do that because a cold only lasts a week and because the bioavailability to your other tissues besides your nose and throat is going to be a lot lower with the zinc acetate lozenges So it’s possible that you don’t need to worry about the copper that much, but I don’t think it can hurt to take a few milligrams like three to six milligrams of copper a day for a week either. So I think it’s a safe, like it’s just a backup sort of insurance policy to protect yourself against copper deficiency while you’re taking these.

54:13   My story with Life Extension zinc acetate lozenges

So here’s my story. After I did this research, I was like, okay, this has to be in my first aid cold kit. So I had some on hand. And when you’re talking about an individual anecdote, it’s almost impossible to say what the effect was because you don’t know what would have happened had you not done what you did, but I do think that I basically cured myself of the common cold. So what happened was I was in some situation where I was around some sick people. I noticed myself sneezing a lot. I tend to be a sneezer, but this was above my usual baseline and it was pretty typical of what happens the day before I develop serious cold symptoms when I get a cold. So I started taking the zinc acetate lozenges in the manner that I just described to you, and basically what happened was for three or four days I would develop that sneezing problem again whenever it had been more than a few hours since I took the last zinc lozenge. This was most notably in the morning when I would wake up, and it was sometimes the case where I would wake up in the middle of the night and I would be sneezing, feel like the beginning of a cold, I would go take the zinc acetate lozenge and it would take a half an hour to dissolve, it would go away and I would fall asleep and everything would be fine. And I had this vague sense over those four days that something was kind of moving into my throat and lungs a little bit, but it never really materialized into anything serious.

Now, at that time I also was taking a few other things that are mentioned in my cold kit, so it’s N equals 1 and it doesn’t mean anything on its own. But it’s anecdotal experience, it’s randomized controlled trials, it’s meta-analyses of those randomized controlled trials, and it’s all of the mechanistic data about how zinc should be effective. That all converges on the point that zinc acetate lozenges used in the manner that I’ve described herein are very effective against the common cold. I can’t recommend these enough as being a basic part of your cold season first aid kit. If you don’t get colds at all because your nutrition is so dialed in and you have the right genetics and you have the right characteristics of your nose and throat that are just totally resistant and it doesn’t apply to you, then awesome. But I’m willing to say that for most of us that’s not the case. I know for myself, nutrition has a really powerful effect on my health, but it doesn’t make me immune to colds. So this is definitely something I’m going to follow, definitely something that I’m going to recommend.

Again, for buying recommendations, see chrismasterjohnphd.com/zinc. For the show notes including the transcript when it’s available and the links to the relevant research, just go to chrismasterjohnphd.com/30. And if you want access to my newsletter and the original email that I had sent out that has the other recommendations for cold season called My Cold Season War Chest of High-Impact Supplements, go to chrismasterjohnphd.com/colds.

All right, I hope this is been helpful. Happy holiday season and happy immunity to cold season. I’ll see you in the next episode. Signing off, this is Chris Masterjohn, Ph.D. of ChrisMasterjohnPhD.com.

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